4 Operation4.9.3 Application Example of Safety Functions4-664.9.3 Application Example of Safety FunctionsAn example of using safety functions is shown below.(1) Connection ExampleIn the following example, a safety unit is used and the HWBB function operates when the guard opens.When a guard opens, both of signals, the /HWBB1 and the /HWBB2, turn OFF, and the EDM1 signal turnsON. Since the feedback is ON when the guard closes, the safety unit is reset, and the /HWBB1 and the /HWBB2 signals turn ON, and the operation becomes possible.Note: The EDM1 signal is used as a sourcing output. Connect the EDM1 so that the current flows from EMD1+ to EMD1-.(2) Failure Detection MethodIn case of a failure such as the /HWBB1 or the /HWBB2 signal remains ON, the safety unit is not reset whenthe guard closes because the EDM1 signal keeps OFF. Therefore starting is impossible, then the failure isdetected.In this case, an error in the external device, disconnection or short-circuiting of the external wiring, or a failurein the SERVOPACK must be considered. Find the cause and correct the problem./HWBB1+ 436587A1A2T11 T12 T21T31 T32 T33 S24 S14T22/HWBB1-/HWBB2+/HWBB2-EDM1+EDM1-0 VCN8SERVOPACKOutput24-V powersupplyGuardSafety unit G9SX-BC202manufactured by OMRON Corp.FuseCloseLimit switchPowersupplyinputInputReset/feedbackinputOpen
